Slashdot Mirror
Titan Photos and Sounds
ahsile writes "NASA and the ESA have released the first images
from Titan. The ESA also has available sounds from the surface." Reader ZZip writes: "Apparently a bunch of enthusiasts has compiled the first mosaics from the raw data delivered by the Huygens probe. Meanwhile space.com has more coverage and pictures from NASA/ESA." Say a silent thank-you to the persistent troubleshooters of the world, without whom none of this would be possible.
If you look at the caption for the photograph on that page, you'll see: "I have bumpmapped the image for clearer details: (the "craters" you might see are photographing artefacts that only seem to be craters)" Still it was a very good observation to notice those... and maybe there's something to it?
Keep the lighting conditions in mind: the Sun is MUCH dimmer out there, even without such a thick, cloudy atmosphere to dim it further. And no, maybe they didn't have a much better camera: there might be severe bandwidth and weight limitations involved.
I think the whole titan mission is fascinating, but they really need to release some higher quality pictures.
Have some patience people. We are mostly seeing raw dumps with quicky contrast enhancement. It will take a while before it is put together and cleaned up.
I would note that Huygens was not designed to be a high-resolution photographic mission. Many were not even sure if the surface would be visable when launched. Plus, such an atmospheric desent probe cannot have directional antennas (other than maybe "not down"), reducing the bandwidth. For example, the mars rovers only send high-res images when they are sitting still and focusing their narrow-angle directional antennas at specific locations in the sky for the receivers to pick up (either at earth dishes or in Mars orbit).
Table-ized A.I.
I was a little saddened after seeing the pictures and getting all stoked for ultra-high-res pictures like what Spirit and Opportunity are sending back, but I don't think it's in the cards.
The uplink from Huygens to Cassini was only 8kb (don't remember if it was bit or bytes, in any case, not a wide channel) and there was only about a 2 hour window to transfer to data before the batteries on Huygens went dead. I consider 2 hours pretty remarkable given the extreme conditions is going in to and the fact that the batteries have been waiting for seven years. The technology also dates to at least 1997, probably earlier (to provide time to check for reliability against radiation fun from space).
Supposedly there are some 350 or so pictures, so at 32Kb a piece (at least what the ESA is putting up), I don't think we're going to see anything much higher.
My Slashdot account is old enough to drink...
It has to do with resolution. With B&W, one pixel measures the gray-level, whereas with RGB, you need three pixels to measure each primary color. So while the images are not as 'colorful', they contain more (acurate) information. The rover missions use B&W for just this reason.
As for the cripsness of the images, I don't know. Perhaps the atmosphere has a lot of haze, or these are just preliminary low-res images. Maybe the hi-res images are coming later. Again, the Rover mission did the same thing initially.
No need for a math PhD. Orbital mechanics is pretty straightforward. Sophomore-level physics for the baseline calculations. The real challenge is in getting the engineering of the spacecraft to be so robust, and to account for more subtle effects (e.g. small changes to trajectory and spin rate due to outgassing and radiation pressure).
Its because the normal way of taking colour pictures (Si photocells with wideband colourfilters) is only good at taking pictures for human eyes, not for any kind of spectral analysis.
Plus in this case, there were 3 reasons:
a) There wasnt enough space for multiple cameras/spectrometer
b) Most of the pictures were planned to be taken in rapid descent/being shaken around (they hoped it would land, but werent sure), so filter changing wouldnt be so good (plus too time consuming, they only had so little)
c) There isnt much light there, so narrowband spectral filters would have made the exposure matter even worse(by factor of 50 or so, and even wideband filters would block 2/3s of the light) (especially combined with the moving viewpoint)
At least they had very cool ccds (little noise), so they could take such bright pictures in that short time.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
No, not because of him. It appears (though no one wants to say anything really substantiative) that someone forgot to send a command to cassini to turn on the reciever for one of the channels. ESA is accepting full responsibility though since it was them who were supposed to give the command to NASA to send up I think.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Thanks to all slashdotters to help test whether our box is capable of coping with the /. effect.
I hope you all like the pictures we created and published before ESA came out with theirs.
Much kudos to ESA, NASA and uni of Arizona for having those pictures out for the world to enjoy
--- Sigmentation Fault - Comments Dumped
So, why do we keep sending only B&W cameras on these things?
Because that's just how cameras (even film) work. Your $100 webcam only senses brightness, not color, just like the cameras on Huygens and the Mars rovers. With the rovers, they have filters which only allow certain frequencies (colors) to hit the sensor, just like your digicam/webcam/film camera. The difference is the filters on the consumer camera are fixed on the CCD (or film), while NASA's are in front of the lens, so you can mix and match.
If your goal is *only* to make pretty pictures, sure, send up a digicam. If your goal is science, you use interchangeable filters, or just a single, fixed filter across all pixels.
This is not only better science, but also higher resolution. Your digicam (say, 4MP), has 2million green pixels, 1 million red, and 1 million blue (in one common configuration, there are other mixes and colors), and the raw image is processed to simulate 4 million RGB pixels. But using a 4MP sensor with filters over the lens, you get all 4 million pixels at the selected wavelength. This provides more information, and science is all about information.